5-95-J01

An Improved Model for Fixed-Bed Coal Combustion and Gasification: Sensitivity Analysis and Applications

Ghani, M.U.; Radulovic, P.T. and Smoot, L.D.
Fuel, 74:1213-1226, 1995. Funded by ACERC and US Department of Energy/Morgantown Energy Technology Center.

Detailed sensitivity analysis and applications of an improved, comprehensive, one-dimensional model for combustion and gasification of coal in fixed beds, FBED-1, are presented. The effects of the devolatilization, oxidation and gasification submodels on the model predictions are discussed. The product gas compositions predicted by various options for gas-phase chemistry are shown. The effects of five model parameters and on operational variable on the predictions of the model are also presented. The sensitivity analysis presented is quantitative since the boundary conditions for both the feed coal and the feed gas streams are satisfied exactly. The utility of the model as a design and analysis tool is demonstrated by simulating two gasifiers: and METC medium-pressure gasifier, and a PyGas high -pressure staged gasifier. Submodels and areas that need further improvements are identified; among these are submodels for large-particle devolatilization, oxidation and gasification and a robust solution method suitable for stiff, highly non-linear problems. Additional features that should be implemented to develop a model for general industrial applications are also identified. These include provisions for additions and withdrawals of gases at multiple locations and options for different flow configurations.